Unicom

May 2001 Issue




Twick or Tweet

Spin recovery technique may vary, but the concepts remain the same

I enjoyed reading the article “Spinning a Tangled Web” by John Lowery [Airmanship, April], however, some of his references to the T-37 spin characteristics and recovery procedures are incorrect. I have over 3000 hours instructor pilot time in the “Tweet” and John’s “interpretation” of the spin procedure is one of the “little things” that frustrated a lot of us IP’s in Undergraduate Pilot Training.

Instructor training offered some real student interpretation challenges also, especially from instructor candidates coming from Century series aircraft. The T-37 spin recovery procedure calls for “Throttles idle, rudder and ailerons neutral, stick – abruptly apply full AFT and hold, determine direction of rotation, abruptly apply full opposite rudder (opposite turn needle) and hold, after one turn, abruptly apply full forward stick until nose pitches down. Neutralize controls and recover from the ensuing dive.”

He makes the statement “add opposite rudder if you could determine the direction of rotation, but the airplane’s rotation rate was extremely fast and sometimes disorienting.” I would believe the statement, assuming he forgot about the step to “abruptly apply full aft stick” and he didn’t look at the turn needle. Any control deflection other than as the procedure states, would result in acceleration of the spin. The highest rate of rotation could be achieved by slowly applying full opposite controls i.e. full forward stick, full opposite rudder and full anti-spin aileron.

Unless the correct finesse was used in applying the controls, the aircraft would recover before achieving full deflection of the controls. Applying the full nose-up elevator characteristically causes the spin to be at its lowest rate of rotation and the best part is that if the aircraft was in an inverted spin, it would recover almost immediately with the application of the nose-up elevator.

The turn needle always indicates the direction of spin rotation.

-Harv Peterson
Via e-mail


John Lowery replies: The Tweet’s spin recovery procedure has evolved over time based on various accidents. In fact following a couple accidents years ago Air Training Command deleted spins altogether. This of course was a big mistake.

Over the years the T-37’s exceedingly fast spin rotation rate has been a problem. The initial application of full aft stick is, as Mr. Peterson says, to keep the spin rotation rate slow enough that the pilot has time to identify spin direction.

I did not intend to describe the entire Stan-Eval procedure, or the effect of inertial moments or roll coupling, but only cover the fact that the full forward stick was valid for recovering the Tweet but a killer in the Century Series fighters.

I bow to Mr. Peterson’s superior knowledge of the T-37, but the point remains valid. To recover from a spin, the Century fighters that I flew all required stick full aft and aileron with spin direction, along with opposite rudder. If you used the full nose-down procedure then the aircraft went inverted upon recovery, with the results shown in the article.

The Piper Tomahawk also has a potentially very fast and disorienting spin mode, which is addressed in the POH. In this case a delay in applying forward stick can significantly lengthen recovery.

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Teach Me Right
I would like to say that I think your article regarding spins hits several very relevant nails on the head.

I am a private pilot who, after getting bored with general flying, decided to pursue aerobatics as a source of enjoyment. I purchased a Yak 52.

My first demo flight left me both enthralled by the possibilities and aware of my complete inexperience to deal with it. My purchase included 25 hours of training from a former Soviet aerobatics pilot.

First I mastered normal spins. It takes at least two turns for the spin to develop properly and the recovery is standard: Remove power, opposite rudder and forward stick.

Then I went on to flat and aggravated flat spins. These maneuvers are as different from regular spins as a scooter is from a big motorcycle.

The recovery from a fully flat developed spin in a Yak 52 is 1. Remove power. 2. Apply full opposite rudder at the same time as you apply full forward stick and full pro-spin aileron. 3. When you think that you have done point 2, you need to push some more.

Initially the speed of rotation increases due to the pro spin aileron but the recovery is much quicker with a much-reduced altitude loss when compared to the standard no-aileron approach. It is, however very important to remember that all control inputs should be neutralized the instant the nose drops.

Hold the inputs for a fraction of a second too long and the aircraft will go straight over and spin flat on its back – and the flip is quite pronounced.

I am a true believer in spin training. I think it is hard to find an instructor who is qualified to teach these maneuvers well. Most instructors today have very little exposure to the skill.

I think that if an instructor is going to teach spins that instructor should have at least encountered and been trained in all aspects of spinning – horizontally and vertically, normal and flat, right side up and upside down. They should also be current.

-Gus Fraser
Via e-mail

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The Family that Breathes Together
I appreciated your article on carrying hazardous materials [Reality Check, March].

I have wanted to use dry ice to transport frozen food on a two-hour flight in my Dakota under Part 91. It’s just family.

How do I go about it safely? I would be grateful for any guidance you could give me.

-Art Seigel
Via e-mail


Pat Veillette replies: While dry ice may seem like an innocent enough chemical because the evaporative gas – carbon dioxide – is considered to be an inert gas, you should be aware that carrying dry ice in a confined area can be quite dangerous to your health.

Dry ice is banned from many commercial aircraft because it produces vapors that cause dizziness or asphyxiation without warning.

It is not allowed in parts of the aircraft carrying people or where the air is exchanged from one part of the aircraft to another. Contact with the gas may cause burns, severe injury and/or frostbite.

But hey, it’s your family.

The gas is non-flammable, though any container of dry ice may explode when heated.

Since the vapors are heavier than air, it will tend to collect in low or confined areas – and a passenger cabin or cockpit is a very confined area.

So perhaps you have considered placing the dry ice in a tightly sealed container to guard against the danger of leaking gases causing dizziness or asphyxiation. In doing that, you create a pressure vessel, and those have inherent risks.

The situation gets even worse if you have a fire. The sealed container may explode or become a projectile. If you have placed the dry ice in an enclosed container and hear a rising sound, the Emergency Response Guidebook recommends withdrawing immediately. In flight, that’s going to be quite difficult.

The recommended first aid in the event of being overcome by dry ice includes moving the victim to fresh air, calling 911 or emergency medical services, applying artificial respiration if the victim is not breathing, and administering oxygen if breathing is difficult. Ensure that medical personnel are aware of the materials involved and take precautions to protect themselves.

So my answer is there really is no cost-effective way to fly your family safely with dry ice on board. Dry ice in even small quantities is hazardous to the safety of light aircraft flight.

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Keep Your ADF, I’m Going for Data
Commenting on Neil Thompson’s letter “Give Me Freedom, Give Me ADF” [Unicom, April]: If Neil would load the NDB or Outer Marker as a waypoint or destination into one of his fancy Garmin 430s, he could use that for both location and distance to and from the fix with far more information than his ADF gives him.

In fact, entering the navigation fix into the GPS when performing all non-GPS approaches is a good idea for supplemental information and the map.

Using the OM as a destination (“Go To”) also works well on an ILS for those majority of airports where the ILS does not have a collocated DME, now in the new localizer-DME database set, since the airport locator is not accurate for approaches using the ILS or LOC. The OM/NDB at the FAF is a more accurate fix and will give “distance from” (shown on the approach plate) for use during the approach.

-David W. Dodson
Via e-mail

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Polishing Skills on a Budget
“Rust Removal” [Instrument Check, April] offers some great advice.

In considering the use of a PC flight simulator, I do have one question. I’m a relatively new pilot, IFR certified as of a few months ago, renting Cessna 172s and 182s.

My PC is a Pentium with a few GB usable space on the hard drive. Please recommend a flight simulator, preferably for under $1,000.

-John Eberle
Via e-mail


There are two distinct pieces to consider, the software and the hardware. You can set up a rudimentary sim with Microsoft Flight Simulator 2000, a yoke and pedals from a local computer store for maybe $300. While more than a toy, it’s of limited training value. You can use it to work on a scan, but little more.

Better, in our view, is a product like the Elite 6.1, which is a serious piece of IFR training software. Then use whatever funds you have left to get the best stick/yoke and rudder hardware you want to afford. Make sure the stick or yoke has a trim control. Other than that, the quality is in the eye of the beholder. You’re not training your hands, you’re training your brain. The hardware won’t make you think you’re really in an airplane, so don’t sweat it.

Our personal hardware is a Virtual Pilot yoke and Thrustmaster pedals, and the performance is acceptable, though not stellar. These are several years old, so there may be better equipment on the market.

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What’s With the Show-Offs?
Your “Crazy Stunts” article on the Air Force pilots [Risk Management, September] struck a painful chord with me.

Eight or ten years ago at a small and remote Mexican resort hotel in Baja called Punta Chivato, I arrived to learn that the previous day a man who was a former Air Force pilot had departed for home with his wife, son, and son’s fiance in their Bonanza. The accident site was an ugly area covered by dirt moguls.

Right next to the area was a small dwelling where Mexican help lived. The engine, and pieces of twisted wreckage were scattered everywhere. The Mexican family explained how all four had lived – for 10 minutes or so. The Mexican family carried each of them to the porch of the little house some 40 feet from the wreckage and tried to comfort them. It spoiled our trip and left an everlasting imprint.

As they left the patio for the airplane that morning, the pilot advised his friends and guests to “get the cameras ready.” He made a high-speed pass by the breakfast patio at 20 feet above the water. Some 1800 feet later he pulled up sharply and executed a hammerhead turn. It worked. But one pass was not enough that Sunday morning.

He climbed, passed overhead and began another high speed run – right at the patio. This time, the Bonanza faltered in the turn and impacted the dirt mounds. Their day was over. Someone has this on video.

A few years later, as we ate breakfast on the same patio, a twin came past 15 to 20 feet from the patio and 20 feet over the water. He climbed out and turned north. The problem here is obvious. The solution is not. Few people do these things, except under certain conditions and in certain places.

Combine any number of variables: foreign setting, no risk of law enforcement, pressures to show off, onlookers, or just plain too much of a sense of personal power to believe there will be consequences, and the ingredients for tragedy are present.

The rarity of tragedy is shocking in light of the frequency of idiotic decisions by pilots. Thanks for the warnings.

One only hopes they mean something to enough people. Your readership is tiny while the pool of fools is vast.

-James Platler
Via e-mail

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Small Consolation
I am a private pilot with 500 hours. I’m IFR rated and own my own plane. I’m not good enough to be a professional pilot, but I am good enough to want to learn as much as I can to protect my family, myself and others when flying.

I find the response by Mr. Regish [Unicom, January] to “Educational Trip” [Learning Experiences, November] to be way out of line. Mr Blair, who wrote the original article, shared an experience with your readers by telling us of an embarrassing situation that happened to him. I learned from Mr. Blair’s story, but I learned nothing from Mr. Regish’s response.

To know that a pilot as experienced as Mr. Blair can make the mistake he described will definitely cause me to think twice before turning onto an unfamiliar taxiway or runway. I hope I never become “too good” a pilot to not learn from others.

Mr. Blair, thank you for sharing your thought-provoking story. I have a few stories I could tell on myself, but I don’t have the fortitude to put them in print.

-Samuel Blackmore
Via e-mail

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Definitely an E-Ticket Ride
Any chance of contacting CFII/chief pilot Charlie Summers, author of “Dogfighting Thor” [Weather Tactics, March]?

I’d pay for a ride in that T-28 into a thunderbuster. I think they could beneficially offer a seat for pilots to experience firsthand what a storm can throw at you, as done for hypoxia in altitude chambers.

-Albert Ishkanian
Via e-mail


If such a ride ever became available to the public, you can bet we’d get in line. Unfortunately, the research grants used to fund Summers’ program don’t allow passenger trips. That doesn’t mean that someone, somewhere won’t do it. If you can buy a trip to the Space Station, you can surely pursue something more earthly, given enough cash.

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New Ain’t Necessarily Better
I own a 1999 Saratoga that is still under warranty. It has had a very long list of failures, many safety-related.

Do you do articles on any of the following: a) ways to deal with manufacturers (and or A&Ps) in addressing quality control issues, b) experiences in anticipating and preventing problems on newer airplanes, c) the ratio (or degree of risk) of failures on newer aircraft vs. “more experienced” aircraft, d) the reliability of different manufacturers.

My message to readers is not to get lulled into a false sense of safety just because the aircraft is fairly new. When you buy new or newer aircraft, be sure there is an understanding of the support you will get for equipment failure. Some warranties will not cover getting the plane to the shop, which tempts pilots to fly an unsafe aircraft to get service work. When you buy, consider the manufacturer and look at the reliability history.

-Gary Schmidt
Via e-mail


Your points raise some good grist for the article mill, and we’ll do what we can in upcoming issues to address some of these topics.

Some general observations: The industry has long held that old airplanes are reliable if maintained properly. However, the level of maintenance is all over the board, so generalizations are difficult to make.

People tend to draw parallels between airplanes and cars. You’d expect a 25-year-old Chevy to have a few problems, but a 2-year-old Camry should be a 100 percent dispatch scenario.

Quality control has been spotty for many aviation manufacturers, not just Piper, in large part because of the fact that so much of the labor is done by hand.

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Mustang Sallied
“Demon Speeds” was a very interesting article on flutter [Risk Management, April]. It is a subject that most pilots know little or nothing about. My one and only experience with flutter shows you that no airplane is exempt, and even the tiniest things matter.

Many years ago, in the early ’60s, I was taking a movie photographer buddy for a ride in the back seat of a P-51. The purpose of the flight was to get some in-cockpit movies of the Mustang’s tailspin. (The P-51 had a very unusual/uncomfortable spin.) For the film, we needed lots of altitude because it took a fair amount to recover, and a clear stretch of coastline below. We wanted to use the coast because it would make it easier to count the turns of the spin in the film.

We climbed to about 14,000 feet, but the coast was clouded over. There we were, all that energy (altitude) stored up, and no good use for it. It also seemed that a mutual friend lived on a ranch nearby. Now I won’t go into all the details, but I was much younger, and there was no 250-knot speed limit below 10,000 feet in those days. We somehow ended up passing over his house at about 500 feet at a bit under 450 KIAS.

As we pulled up, the rudder fluttered. It was violent. No instrument was readable and the rudder pedals were vibrating through 3-inch arcs at about a 60 cycle rate. It felt like you were standing on one of those old foot massagers gone crazy.

I chopped the power and pulled the airplane vertical to get slowed down as quickly as we could. As we backed through about 170 knots the flutter stopped. We recovered, and very carefully flew back to the airport. I might add that I was considerably older and much more conservative than I had been at takeoff.

Coincidentally, a couple of nights later at a party, I met a guy who was an aeronautical engineer whose specialty was flutter. When I described our encounter with flutter, he congratulated me on joining the Caterpillar Club, and wondered why he had not read about the crash. He was flabbergasted when I told him about flying the airplane back and landing it in one piece.

Investigation determined that the cause of the flutter was a single coat of paint applied to the fabric rudder without a re-balance.

As a matter of interest, the only damage to the airplane was half a dozen loose rivets in the aft fuselage, a few instruments reduced to dust, and two (out of three) broken hinges on the rudder trim tab. I don’t have any idea what would have happened if the last hinge or the rudder trim tab push-rod had let go.

Please withhold my name. I would prefer that my kid, a nice commercial airline pilot, not know what a checkered past exists in his gray-haired old man, at least not yet.

-Name Withheld